1. Field of the Invention
Certain inventive aspects relate to an optical-information recording apparatus and method and a signal processing circuit for the same, and more particularly to an optical-information recording apparatus and method and a signal processing circuit for the same, that can optimize the recording condition in accordance with the compatibleness of the drive with a media.
2. Description of the Related Technology
Where recording is made to an optical-information recording media (hereinafter referred to as a “media”), as represented by a CD-R, a DVD-R or the like, the compatibleness of the recording media with the recording apparatus (hereinafter referred to as a “drive”), used in the recording, is different from combination to combination on an individual basis. This can be considered attributable to the cause of a media-side factor that changes the optimum condition due to a different recording material forming the media and a change in the optimal recording condition resulting from the deposit-film variation as encountered in the manufacture thereof, and of a drive-side factor that changes the optimum condition due to a different-type optical pickup and semiconductor laser constituting the drive and a change in the optimal condition due to the variation of assembling as encountered in the manufacture thereof. In actual, there exists a recording condition well suited for each combination as a composite factor.
For this reason, it is a traditional practice to use an approach to previously store, on the media side, ID information whose media type is identifiable from the drive side and, on the drive side, a recording condition previously prepared for each media type so that, when performing an actual recording, the ID information about the relevant media can be read out of the media loaded on the drive thereby using a recording condition (called a “write strategy”) related to the ID information.
With the existing technique, recording conditions can be selected properly to a certain extent for a known media verified previously. However, for an unknown unverified media, there are cases not to be coped with under the recording condition prepared. Besides, there encounters a case that a media, even if known, is not compatible with under the prepared recording condition in the presence of a certain environmental change, e.g. change in recording rate, disturbance or aging.
There are known approaches described in JP-A-2003-30837, JP-A-2004-110995 and JP-A-2000-231727 that are intended to cope with such unknown medias.
JP-A-2003-30837 describes, in paragraph 0020, that “ . . . detects a phase error of from the channel clock, on each record pattern. The record-compensation-parameter regulating section 12 optimizes the emission-waveform rule depending upon the result detected in the phase-error detecting section 11. . . . ”, thus disclosing a technique to detect and compensate for a phase error through a comparison with the channel clock.
This document also describes, in paragraph 0024, that “then recorded is a test pattern for determining an emission-waveform rule. Then, reproduction is done from the area where recording the test pattern, to examine the previously-prepared relationship of the emission-waveform rule with a phase error amount. Namely, measurement is made as to a phase-error amount in each combination of a length of various marks and a length of various spaces immediately preceding those marks. From the phase-error amount thus measured, predicted is an emission-waveform rule on which the phase-error amount is zero, to determine a desired emission-waveform rule. . . . ”, thus disclosing a technique that measures a phase-error amount on each combination of a mark and a space and predicts an emission-waveform rule on which the phase-error amount is zero (see FIGS. 8 and 12).
The technique described in JP-A-2003-30837 is an art effective in optimizing the strategy because of performing a correction based on a phase error in the record pattern.
However, the technique in JP-A-2003-30837 is to finely regulate the strategy previously stored in the drive similarly to the existing ones. For the media not adapted for the strategy previously stored, preferred recording quality is difficult to provide satisfactorily.
Meanwhile, JP-A-2004-110995 describes, in paragraph 0045, that “ . . . integrally (continuously) produces a top pulse corresponding to a period 3T and a non-multi-pulse corresponding to a period 8T . . . ” and, in paragraph 0046, that “ . . . although the write pulse is regulated in its laser power in two stages, the optimal power is obtained at an optimal ratio of the laser power (top-pulse wave height) Ph to the laser power (non-multi-pulse wave height) Pm . . . ”, thus suggesting the usefulness in optimizing the ratio Ph/Pm.
However, the technique in JP-A-2004-110995 is to temporarily establish the initial values of Ph and Pm depending upon the values stored in the drive or the media, and then determine the ratio Ph/Pm. This makes it difficult to satisfy a well recording quality to the media not adapted for the value temporarily established, similarly to JP-A-2003-30837.
JP-A-2000-231727 describes a technique that corrects for a phase error in the record pattern, similarly to JP-A-2003-30837. However, in case merely performing a phase correction, there is a possible case that, on a certain media, the modulation factor be excessively great for a long code. With a great modulation factor, the pit is increased in its width or depth. Where those are excessively great, signal quality deteriorates at the wobble or the land pre-pit (Lpp).